In what way were the events surrounding the end of World War II different than World War I?

The major difference between these two is that World War II ended very definitively while World War I just sort of fizzled out with Germany's surrender.

In WWI, Germany was not decisively defeated. They realized they were not going to win, so they surrendered. But when they did so, they were still in France. There was no invasion of Germany. It did not feel to many Germans like they had really lost the war.

By contrast, everyone knew the Axis had clearly lost WWII. The Allies invaded Germany and took Berlin. The Americans advanced to the doorstep of Japan, bombed the main islands terribly and eventually used atomic bombs. In both cases, it was completely obvious that Axis countries had been defeated in a way that it was not obvious at the end of WWI.